1. Field of the Invention
The present invention relates to a film splicer for joining ends of films to be spliced with an adhesive tape, and to a film carrier tape for mounting electronic components that is spliced by the film splicer (such film carrier tapes including TAB (tape automated bonding) tapes, COF (chip on film) tapes, BGA (ball grid array) tapes, CSP (chip size package) tapes, ASIC (application specific integrated circuit) tapes, 2-metal (double-sided wiring) tapes and multilayer wiring tapes). More particularly, the present invention pertains to prevention of steps at edges in the width direction of spliced films. Herein, the term “film carrier tape(s) for mounting electronic components” comprehends those carrying electronic components as well as film carrier tapes prior to the mounting.
2. Description of Related Art
Various film splicers have been proposed and been in practical use for splicing the ends of two films with an adhesive tape (see, for example, JP-A-2002-28981). For example, such film splicers are employed to splice film carrier tapes for the mounting of electronic components (hereinafter, sometimes referred to as “film carrier tapes”) or to splice a film carrier tape and a lead tape by joining the ends thereof with an adhesive tape.
It is common practice that a film carrier tape having a length of 110 m per lot is cut into 20-40 m long tapes depending on user specification, and lead tapes are spliced with the tip and end of each tape to wind the tape around a reel.
Moreover, when any defective part is found during production of film carrier tapes, the area corresponding to the defective part is cut off and the resultant ends of the film carrier tapes are spliced.
FIG. 9 shows an example of the conventional film splicer, and FIG. 10 illustrates punching members and adhesive tape-cutting blades attached to the splicer. The illustrated film splicer 101 has the following mechanism. Two film carrier tapes 121 having been trimmed by a cutter 115 to remove unnecessary portions are guided by a pair of guide members 116 and 117, and splicing ends 122 are butted together on a film splicing table 113 arranged on a base body 102. Film pressing members 118 are folded on the film carrier tapes 121 to hold the same. Subsequently, an adhesive tape 124 is drawn from a roll 119 fitted in the base body 102 and is applied to splice the splicing ends 122 of the film carrier tapes 121.
Thereafter, a splicer arm 104 whose base end is supported by a shaft to the base body 102 to allow rotation toward and away from the base body 102, is pressed down against the upper surface of the base body 102. As a result, a pressing plate 105 fitted to the lower surface side of the splicer arm 104 presses the film carrier tapes 121 and the adhesive tape 124 against the film splicing table 113. At the same time, a pair of punching members 111 as illustrated in FIG. 10 is protruded downward through punching member penetration holes 106 of the pressing plate 105. The punching members penetrate the adhesive tape 124 and are fitted in punching member fitting holes 108 formed in the film splicing table 113, with formation of sprocket holes.
When the splicer arm 104 is pressed down against the upper surface of the base body 102, a pair of adhesive tape-cutting blades 112 as illustrated in FIG. 10 is protruded downward from the surface of the pressing plate 105 and fits with the edges 109 in the width direction of the film splicing table 113 to cut the adhesive tape 124 to the length in the width direction of the film carrier tapes 121.
However, a width of the insulating layer (e.g., polyimide film) of the film carrier tape varies by about ±100 μm. Accordingly, it is often the case that the widths of such film carrier tapes do not correspond to a predetermined distance between a pair of the adhesive tape-cutting blades 112, and insufficient or excessive tape widths result.
When the widths of the film carrier tapes are larger than the distance between the adhesive tape-cutting blades, it is required that the cutting blades will cut the adhesive tape and also the excessive edge areas in the width direction of the film carrier tapes. However, the conventional cutting blades (cutters) 112 with a sharp tip sometimes fail to cut film carrier tapes such as TAB tapes.
Even if the cutting succeeds, the cutting blades will cut off the excessive edge areas in the width direction of the film carrier tapes 21 to leave the concave edges with formation of right-angled steps 36 as illustrated in FIG. 11.
When the widths of the film carrier tapes are smaller than the distance between the adhesive tape-cutting blades, the adhesive tape will be cut outside the edges in the width direction of the film carrier tapes. Consequently, the adhesive tape will protrude from the edges in the width direction of the film carrier tapes to form convex steps.
The steps formed at the edges of the film carrier tapes as described above cause troubles in the conveyance of the film carrier tapes. For example, when the film carrier tapes are moved in the mounting process of electronic components such as IC tips, the steps are caught in guide members of approximately the same width as the film carrier tapes that regulate the conveyance position of the tapes.
The present invention has been made to solve the aforesaid problems of the background art. It is therefore an object of the invention to provide a film splicer that is capable of cutting an adhesive tape with edge areas in the width direction of films such as film carrier tapes and that does not leave steps at the edges of the films spliced together. The invention has another object of providing a film carrier tape free from such steps.